References to religious facts were gathered quickly. If I haven't nailed all the subtleties of your particular belief system, I ask for understanding that it is not a knock on your belief system. Corrections are welcome in the comments, but please reference them if you do.

Hanukkah involves the lighting of the Menorah every night.

The name is actually a slight misnomer when used in reference to Hanukkah. A menorah has seven branches with candles, and it symbolizes creation. It is often lit on the Sabbath. But a Hanukkiyah, or Hanukkah menorah, is lit on the eight days of Hanukkah, and has nine branches. One of the candles helps light the others over the eight days—a subtle but interesting difference.

Christmas is the biggest Christian holiday.

Nope, Easter is!

Although you would never know that if you live in the United States. Christmas is a beloved but minor Christian holiday. Easter is the major holiday for Christians with more than a month of celebration leading up to it. The reasons why Christmas has become so popular, in my opinion, are really secular and have little to do with the religious aspects.

Christmas trees are an American Christmas tradition.

Not really. The Christmas tree tradition, as we now know it, was started in Germany about the 16th century. The first records of displays in the United States date back to Pennsylvania German immigrants in 1830. There is evidence that Christmas trees were found in some German community homes by the 18th century, but it wasn't until the 1890s that the tree seems to have a significant cultural impact in the U.S. The early 20th century is when the American tradition first changed it significantly. Americans seem to like floor-to-ceiling trees, while European Christmas trees were usually small less than four feet tall. Since the early 20th century it has become an entrenched American tradition—if not a long-standing one (pun intended). George Washington wouldn't know what a Christmas tree was, and it's likely Abraham Lincoln wouldn't have, either.

The Christmas tree as a rallying point for so many religious fundamentalists is a bit of a mystery to me. I am equally perplexed, why so many atheists find Christmas trees on public property so offensive in the United States, since it is essentially a recent tradition borrowed from German immigrants; its true religious significance seems minor, unless you personally give it some. I am a firm in my stance of separation of church and state no matter the nation. Yet scientifically, I know that objections are just semantics—a set of semantics I cannot get to upset about. Atheist purists may be offended; it is no more offensive to me than the Easter egg hunt at the White House, which gets far less public acrimony.

The Dreidel Myth

The common myth (or its variants) surrounding this game is that Judeans were not allowed to practice their religion, they would meet and read Jewish texts secretly. If soldiers of an occupying power came along, they hid the texts and would take out the spinning tops to play, telling soldiers they were just gambling.

Black Friday is the biggest shopping day of the year in the United States.

Actually this is myth! According to the National Retail Federation the biggest retail shopping day of the year, by money spent, is the last Saturday before the Christmas holiday. So procrastinators do win out over standing in lines.

This is not a myth. From Stanley Weintraub's book, Silent Night: The Story of the World War I Christmas Truce:

The Germans set trees on trench parapets and lit the candles. Then, they began singing carols, and though their language was unfamiliar to their enemies, the tunes were not. After a few trees were shot at, the British became more curious than belligerent and crawled forward to watch and listen. And after a while, they began to sing.

By Christmas morning, the "no man's land" between the trenches was filled with fraternizing soldiers, sharing rations and gifts, singing and (more solemnly) burying their dead between the lines. Soon they were even playing soccer, mostly with improvised balls.

According to the official war diary of the 133rd Saxon Regiment, "Tommy and Fritz" kicked about a real football supplied by a Scot. "This developed into a regulation football match with caps casually laid out as goals. The frozen ground was no great matter ... The game ended 3-2 for Fritz."

Often misattributed anecdotally to other conflicts, this "myth" is actually fact. Although the generals on both sides despised the truce and tried to inspire the groups to attack each other, across a broad stretch of the front, for a short time, there was detente on the front lines of World War I. It only lasted about a week in total: with the new year hostilities resumed.

So there is a quick and dirty lists of some holiday myths. I am sure you knew some but I am sure most did not know all.